(269a) Remarkable CO2 Uptakes in MOFs Whilst in the Presence of Water Vapor

The search for solutions for economic CO₂capture from flue gases is ever continuing. Capture using physical adsorption could be viable as long as the right adsorbent is found and indeed amine functionalized materials could be of interest.

Our group is interested in the initial evaluation of various adsorbent materials for a number of different processes. In this respect, Metal Organic Frameworks are a particularly interesting family of materials due to the possibility to vary the metal centre and/or organic linker to give a huge variety of physical and chemical properties. The problem here is that with such a wide variety of materials to hand, which are of interest for CO₂capture ?

Indeed, the capture of CO₂ from flue gases poses a number of problems in terms of low CO₂ concentration (below 20%), low total pressure (1 bar), and the eventual presence of water. Indeed, whilst many MOFs seem to be unstable in the presence of water, some studies suggest that CO₂capture in moderate humidity’s enhance CO2 uptake. This is in contrast with zeolites and activated carbons where water has a detrimental effect.

Our work will show several cases where water plays a determining role during CO₂uptakes in various MOFs. Uptakes are measured using chromatography and simultaneously we are able to directly measure the heats using microcalorimetry.

Two separate cases will be considered : (1) mesoporous MOFs and (2) a bifunctional microporous MOF. These systems will be compared with a reference activated carbon and a zeolite. We show that in each case, considerable increases in CO₂ capture can be attained in the presence of water vapor and we will give tentative explanations of the phenonena in play.